It is known to prepare beverages by separating a mixture consisting of brewed coffee and coffee powder with centrifugal forces. Such a mixture is obtained by the interaction of hot water and ground coffee powder for a defined time. The water is then forced through a screen, on which screen powder material is present.
The existing centrifugal systems suffer the inconvenience that the liquid extract discharged from the device comes at a too low temperature. In particular, the liquid extract is cooled down in the collecting device by heat exchange with the extensive surfaces of the collector of the device. Indeed, according to the principle of the centrifugal process, the brewing unit is rotated along a central axis to form a thin layer or jets of liquid impacting on a substantially tubular impact surface. The liquid comes in contact with and drip from a surface that can be equal, for instance, to a first impact surface if when it is a pure cylinder may have an area of at least about 500 mm2. Furthermore, the liquid is normally collected in a U-shaped cavity that leads to at least one dispensing duct forming again extensive areas of contact with the extracted liquid. Furthermore, the receptacle such as a cup further cools the liquid down unless it has been heated before being placed under the device for the reception of the liquid.
Furthermore, it is known that certain beverage ingredients, such as roast and ground coffee, must be brewed with a heated liquid, e.g., hot water, within a particular range of temperature to ensure the full extraction of the ingredients including the capture of the desired aroma compounds. Therefore, the liquid supplied in the brewing unit cannot be overheated to compensate for the temperature losses endured by the liquid after extraction as it would negatively affect the quality of extraction. The range of temperatures for an optimal brewing such as for coffee or tea must be so respected for ensuring the best quality of the final beverage. Furthermore, other quality characteristics of the coffee beverage must be preserved during preparation such as the head of foam called “crema”.
The present invention aims at providing a device and a method for compensating at least partially the thermal losses of the beverage (or liquid extract) during its production by centrifugation and so allow the delivery of the beverage at a suitable temperature of service.
The invention also aims at providing a device and method that preserves the gustative and foam characteristics of a coffee beverage.